We have to differentiate between an action and an action group.
An Action on its own is more or less a single command.
An action group is a collection of commands.
An action group can/must have a unique name of your choice.
An action (command) naturally has to have a predefined name - otherwise Mp3tag would not understand it.
If I look at your screen dump then it looks to me as though you put all action commands into a single action group. This means: you cannot rename the commands.
You would have to create a new action group (Menu Actions>Actions),
click the "New" button
enter a name that makes sense to you
fill this action group with action commands in the following dialogue.
As the action groups have user-defined names, you can enter special characters to pimp the appearance
& adds the next letter as hotkey
indicates a (grouping) submenu, e.g.
would add the submenu "Track" to the Menu Actions and have 2 menu functions: Counter and Track.
Mp3tag has no dedicated method or option to put remarks or descriptions into actionsgroup scripts.
But within an action "Format value" you may misuse the "square bracket clamb" to store descriptive text.
Example ... see there ... CD´s einer Compilation zusammenfügen